You mean pollen doesn’t equal flowers equals grave? Or area not green in past? I don’t understand.
Tassili-n-Ajjer in Algeria is one of the most famous North African sites of rock painting. Its imagery documents a verdant Sahara teeming with life that stands in stark contrast to the arid desert the region has since become. Tassili paintings and engravings, like those of other rock art areas in the Sahara, are commonly divided into at least four chronological periods based on style and content. These are: an archaic tradition depicting wild animals whose antiquity is unknown but certainly goes back well before 4500 B.C.; a so-called bovidian tradition, which corresponds to the arrival of cattle in North Africa between 4500 and 4000 B.C.; a "horse" tradition, which corresponds to the appearance of horses in the North African archaeological record from about 2000 B.C. onward; and a "camel" tradition, which emerges around the time of Christ when these animals first appear in North Africa.
Engravings of animals such as the extinct giant buffalo are among the earliest works, followed later by paintings in which color is used to depict humans and animals with striking naturalism. In the last period, chariots, shields, and camels appear in the rock paintings. Although close to the Iberian Peninsula, it is currently believed that the rock art of Algeria and Tassili developed independently of that in Europe.